The present invention relates to an optical information recording medium, such as, for example, an optical disk, used for recording and reproducing information optically, an information recording method in which test signals are recorded before the recording of information signals to optimize recording conditions, and an information recording/reproducing apparatus.
Recently, as media used for recording information optically, an optical disk, an optical card, an optical tape, and the like have been proposed and developed. Among them, the optical disk has been receiving attention as a medium on which mass information can be recorded with high density and from which the mass information can be reproduced.
One system of rewritable optical disks is a phase-change type optical disk. A recording film used in the phase-change type optical disk is changed to either an amorphous state or a crystalline state depending on a heating condition by a laser beam and a cooling condition. There is reversibility between the amorphous state and the crystalline state. The above-mentioned amorphous state and the crystalline state are different in optical constants (a refractive index and an extinction coefficient) of the recording film. In the phase-change type optical disk, the two states are produced in the recording film selectively according to information signals. By using the optical change (the change in transmittance or reflectance) thus caused, the information signals are recorded and reproduced.
In order to obtain the above-mentioned two states, the following method is used in recording information signals. When a laser beam (with a power level Pp) focused by an optical head is irradiated onto a recording film of an optical disk in the form of pulse (which is called xe2x80x9ca recording pulsexe2x80x9d) to increase the temperature of the recording film above its melting point, a molten portion is cooled quickly after the passage of the laser beam to form a recording mark in an amorphous state. On the other hand, when a laser beam (with a power level Pb, wherein Pb less than Pp) is focused and irradiated with a power at a level that allows the temperature of the recording film to increase to the temperature above that causing the recording film to change to a crystalline state but below its melting point, the irradiation part in the recording film is changed to a crystalline state. This power level Pb is called xe2x80x9can erase powerxe2x80x9d.
Thus, corresponding to a recording data signal, a recording pattern including recording marks formed of amorphous areas and portions with no mark (called xe2x80x9cspacesxe2x80x9d) formed of crystalline areas is formed on tracks on the optical disk. By utilizing the differences in optical characteristics between the crystalline areas and the amorphous areas, information signals can be reproduced.
Recently, instead of a mark position recording (that also is called xe2x80x9cPPM recordingxe2x80x9d) system, a mark edge recording (that also is called xe2x80x9cPWM recordingxe2x80x9d) system has been increasingly used. In the mark position recording, information is given only to positions of recording marks themselves. On the other hand, in the mark edge recording, information is given to both edge positions at a leading edge and a rear edge of each recording mark, resulting in the advantage of improving recording linear density.
Further, as a method of facilitating rotation control of a spindle motor in a recording/reproducing apparatus while increasing recording capacity in an optical disk, a Z-CLV (Zoned Constant Linear Velocity) format has been proposed. In an optical disk with the Z-CLV format, a recording area is divided into zones including a predetermined number of tracks, and the number of sectors around the disk is increased gradually from a zone in the inner circumference toward that in the outer circumference.
In an apparatus used for recording information on and reproducing information from such a Z-CLV disk, information is recorded or reproduced by reducing the rotation speed of the disk gradually from the inner circumference toward the outer circumference (wherein the rotation speed in each zone is constant) and allowing the linear velocity to be substantially constant throughout all rounds on the disk.
The Z-CLV format is described, for example, as xe2x80x9can M-CLV (Modified Constant Linear Velocity) formatxe2x80x9d in xe2x80x9cOptical Disk Technologyxe2x80x9d, page 223, Radio Technique Co. Ltd., (1988).
Optical disks are exchangeable recording media and therefore recording/reproducing apparatuses for optical disks are required to record information on and reproduce information from a plurality of different optical disks stably. However, even in optical disks manufactured under the same conditions, the optimum power level of a laser beam for recording and reproducing information may be different due to irregularity during the manufacture or aging. Further, because of dirt on the substrate surface of an optical disk, the decrease in transmission efficiency in an optical system or the variation in operation condition in a recording/reproducing apparatus, the power of a laser beam reaching a recording film of the optical disk may vary.
In addition, particularly in the mark edge recording system, the variation in thermal characteristics of an optical disk affects the formation state of recording marks themselves and the degree of the thermal interference between the recording marks. Therefore, the optimum edge positions of recording pulses may be different in each optical disk.
An example of methods of recording and reproducing information signals stably without being affected by such variation in optimum power level of a laser beam or in optimum edge positions of recording pulses as described above has been disclosed in JP 4-137224 A. In the example disclosed therein, after carrying out test recording with a specific data pattern (which is called xe2x80x9ca test signalxe2x80x9d) prior to the recording of information signals, the test signal recorded is reproduced and edge positions of recording marks are determined by measuring the signal reproduced, thus controlling the edge positions of recording pulses to be optimum.
As another example, JP 6-195713 A discloses a technique in which edge positions of recording marks are determined and then at least one selected from edge positions of recording pulses and recording power is controlled. In JP 9-63056 A, a method for determining an optimum recording power based on the power dependency of a bit error rate has been disclosed. Further, JP 7-129959 A discloses a method of controlling edge positions of recording pulses according to the length of the recording marks and the length of the spaces directly before and after the respective recording marks.
On the other hand, a method of increasing the number of times an optical disk can be rewritten has been proposed in JP 9-219022 A. In this method, by inverting the polarity (1 or 0) of a recording data signal at random, the concentration of damage at specific positions on a recording film is avoided, thus suppressing the deterioration of the recording film.
However, in the aforementioned conventional methods, since measured values of edge positions of recording marks vary, errors in determining edge positions of recording pulses may occur, which has been a problem. This problem will be explained with reference to FIGS. 11 to 14 as follows.
FIGS. 11 to 14 show examples of mark distortion caused by the position relationship between recording marks that had been recorded previously and recording marks that have been overwritten. Each figure of FIGS. 11 to 14 shows the state of a track on an optical disk before the overwriting of recording marks in the upper section, a pattern of a test signal (as a recording data signal) to be overwritten in the middle section, and the state of the track after the overwriting of the recording marks in the lower section.
Conventionally, in many cases, a predetermined track is assigned as the track on which recording marks for test recording are to be recorded. In this case, recording marks are overwritten on the predetermined track repeatedly. Therefore, when a test signal (or an information signal) had been recorded on the track on which test recording should be carried out, the shapes of the recording marks that have been overwritten and thus recorded are distorted due to the influence of the recording marks that had previously been recorded.
When using a phase-change type optical disk, amorphous areas (i.e. the areas where recording marks are present) and crystalline areas are different in optical absorption property. Therefore, even when laser beams with the same energy are irradiated, the temperature increase rate in a recording film of the optical disk is different in the amorphous areas and the crystalline areas. Thus, in the case of a disk designed so that optical absorptance in the amorphous areas is higher than that in the crystalline areas, recording marks overwritten tend to be increased in size in the amorphous areas. As a result, edge positions of the recording marks shift in the direction in which the recording marks extend as shown with hatching in FIGS. 11 to 14, which is called xe2x80x9cmark distortionxe2x80x9d. When a disk is designed so that optical absorptance in the amorphous areas is lower than that in the crystalline areas, the result opposite to the above may be obtained.
Therefore, the shapes of recording marks vary depending on the overlap condition between recording marks recorded in test recording and recording marks previously recorded. Consequently, the edge positions of the recording marks vary. When a signal that previously has been recorded on a track is the same as or similar to a test signal overwritten, the overlap condition between the previous recording marks and the recording marks overwritten is always the same unless rotational fluctuation of a disk is great. Therefore, depending on the phase relation between a previous data pattern and a data pattern overwritten, measured values of the edge positions vary.
For example, as shown in the upper section in FIG. 11, when a recording mark is overwritten on a track 111 on which a recording mark 113 previously was present using a test signal with the pattern shown in the middle section in FIG. 11, a recording mark 112 overwritten overlaps with the previous recording mark 113, thus causing mark distortion 114 as shown in the lower section.
In the case where a leading edge position of a recording pulse of 3T (wherein T indicates a clock cycle of a recording data signal) is determined by measuring the interval x between the leading edge of the recording mark 112 and that of a recording mark 115, when the mark distortion 114 has occurred only at the end of the recording mark 112 overwritten as shown in FIG. 11, the mark distortion 114 does not affect the interval x. However, as shown in FIG. 12, when the leading edge of the recording mark 115 of a recording pulse of 3T to be overwritten overlaps with the previous recording mark 113, mark distortion 116 occurs at the leading end of the recording mark 115. As a result, the interval x measured is indicated by xxe2x88x92xcex941.
Further, as shown in FIG. 13, when the leading end of the recording mark 112 of a recording pulse of 10T overlaps with the previous recording mark 113, mark distortion 114 occurs at the leading edge of the recording mark 112. As a result, the interval x measured is indicated by x+xcex942.
As shown in FIG. 14, when both the leading edges of the recording mark 115 of a recording pulse of 3T and of the recording mark 112 of a recording pulse of 10T overlap with the previous recording mark 113, the interval x measured is indicated by x+xcex942xe2x88x92xcex941.
In the conventional methods, an optimum recording power cannot always be obtained after recording pulses have been controlled to have optimum edge positions, which has been a problem. This problem will be explained with reference to FIG. 15 as follows.
FIG. 15 shows the relationship between recording peak power Pp and a bit error rate (or jitter) when a periodic signal of the shortest mark (for example, a recording mark formed by a recording pulse of 3T in the case of 8-16 modulation, hereafter which is called xe2x80x9ca 3T markxe2x80x9d) is recorded while varying the recording pulse width.
When edge positions of recording pulses are adjusted by test recording, the length of the recording pulses (or a recording pulse train) varies. Therefore, the energy applied so that the recording pulses form recording marks is affected by the adjustment of the edge positions. This influence becomes significant particularly when a short mark such as the shortest mark is formed. As a result, the optimum recording power also varies.
For instance, when the length of a recording pulse for forming a 3T mark of the shortest mark in the case of 8-16 modulation is shortened due to the adjustment of edge positions, the energy used for forming the 3T mark decreases. Therefore, the peak power dependency of a bit error rate shifts from g1 to g2 as shown in FIG. 15. Consequently, the optimum recording power (which is generally determined by multiplying the power Pth1 or Pth2 that allows the bit error rate to be a predetermined threshold value Bth by a certain value) becomes higher than that before the adjustment of edge positions.
On the contrary to the above problem, in the conventional methods, optimum edge positions of recording pulses cannot always be obtained after the recording power has been adjusted, which also has been a problem in some cases. This problem will be explained as follows.
When the recording power is adjusted by test recording, the energy applied to a recording film of an optical disk by a laser beam varies. Therefore, even if recording pulses or recording pulse trains have the same length, according to the change in recording power the length, i.e. edge positions, of recording marks formed on a track of the optical disk also are changed. This influence is significant particularly when a short mark is formed. As a result, the optimum edge positions of recording pulses that optimize edge positions of recording marks vary. For instance, when the recording power is increased based on test recording, the leading edge of a 3T mark extends forward and its end edge extends backward. Consequently, the optimum edge positions of the recording pulse for recording the 3T mark cannot be obtained.
In the Z-CLV format, since an optical disk is rotated at a constant rotation speed in each zone, the linear velocity and linear density are different depending on the radius within each zone. In other words, the linear velocity and recording linear density decrease gradually toward the outer circumference within each zone. Therefore, in the conventional methods, when test recording is carried out on an optical disk with the Z-CLV format, an optimum recording power or optimum edge positions of recording pulses cannot always be obtained throughout the whole area within each zone, which has been a problem.
Furthermore, in the method disclosed, for example, in JP 9-219022 A, the polarity of a data pattern is inverted at random even when edge positions of recording pulses are determined by test recording. Therefore, even when the same data pattern is recorded, the relationship between a recording mark and a space (i.e. the relationship between the leading edge and the rear edge of a recording mark) may be reversed depending on the polarity. In this case, the leading edge and the rear edge of a recording mark cannot be distinguished, which has been a problem.
In order to solve the aforementioned conventional problems, the present invention seeks to provide an optical information recording apparatus, an optical information recording method, and an optical information recording medium that enable information signals to be recorded precisely by determining recording conditions such as recording power, edge positions of recording pulses, and the like suitably by test recording.
In order to attain the above-mentioned object, a first optical information recording apparatus of the present invention comprises: a test signal generation means that generates a test signal; a recording means that converts the test signal and an information signal to a recording data signal, drives a light source based on the recording data signal, and records the test signal and the information signal on an optical information recording medium; a recording start point shifting means that shifts a start point for test recording on the optical information recording medium at random in each sector; a reproducing means that reproduces signals from the optical information recording medium; and a recording condition determination means that allows the test signal generation means to supply the test signal to the recording means, carries out the test recording in a plurality of sectors on the optical information recording medium, and then determines edge positions of pulses in the recording data signal based on an average of results obtained by reproducing the test signal from each of the plurality of sectors by the reproducing means.
According to this configuration, the recording start point of the test signal to be recorded in each of the plurality of sectors on the optical information recording medium is shifted at random in each sector. Therefore, recording marks that previously have been recorded in an area intended for the test recording and recording marks of the test signal overwritten thereon overlap in random conditions in each sector. Thus, shifts in interval between edges in the test signal that are caused by mark distortion produced by the overwriting of the recording marks of the test signal on the recording marks that previously have been recorded are averaged. Consequently, variation caused by the phase relation between the recording marks that previously have been recorded on the optical information recording medium and the recording marks of the test signal does not occur in values of the intervals between edges that are calculated from test signals reproduced. As a result, the interval between edges of recording marks of the test signal can be calculated precisely, thus providing an optical information recording apparatus that can record information signals precisely by optimizing edge positions in the recording data signal.
In order to attain the aforementioned object, a second optical information recording apparatus of the present invention comprises: a test signal generation means that generates a test signal; a recording means that converts the test signal and an information signal to a recording data signal, drives a light source based on the recording data signal, and records the test signal and the information signal on an optical information recording medium; a data pattern generation means that generates a data pattern having substantially no correlation with the test signal; a reproducing means that reproduces signals from the optical information recording medium; and a recording condition determination means that allows the data pattern generation means to supply the data pattern to the recording means to record the data pattern in an area for carrying out the test recording on the optical information recording medium, then allows the test signal generation means to supply the test signal to the recording means to overwrite the test signal in the area, and determines a proper value for edge positions of recording pulses in the recording data signal based on a result obtained by reproducing the test signal from the area by the reproducing means.
According to this configuration, before the test recording carried out on the optical information recording medium, the data pattern having substantially no correlation with the test signal is recorded in the area intended for the test recording and therefore recording marks of the test signal overwritten in the area and recording marks that previously have been recorded overlap in random conditions. Thus, shifts in interval between edges in the test signal that are caused by mark distortion produced by the overwriting of the recording marks of the test signal on the recording marks that previously have been recorded are averaged. Consequently, variation caused by the phase relation between the recording marks that previously have been recorded on the optical information recording medium and the recording marks of the test signal does not occur in values of the intervals between edges that are calculated from test signals reproduced. As a result, the interval between edges of recording marks of the test signal can be calculated precisely, thus providing an optical information recording apparatus that can record information signals precisely by optimizing edge positions in the recording data signal.
It is preferable that the second optical information recording apparatus is further provided with a recording start point shifting means that shifts a recording start point at random in each sector on the optical information recording medium to shift the recording start point at least of the test signal at random.
According to this configuration, shifts in interval between edges in the test signal that are caused by the overwriting of the recording marks of the test signal on the recording marks that previously have been recorded can be further averaged, thus optimizing the edge positions in the recording data signal further precisely.
In the second optical information recording apparatus, it is preferable that the data pattern is a random pattern.
According to this configuration, since a random pattern is recorded in the area intended for the test recording, shifts in interval between edges in the test signal that are caused by the overwriting of the recording marks of the test signal on the recording marks that previously have been recorded can be further averaged, thus enabling an optimum value for edge positions in the recording data signal to be determined further precisely.
In order to attain the aforementioned object, a third optical information recording apparatus of the present invention comprises: a test signal generation means that generates a test signal; a recording/erasing means that is operated either in a recording mode in which the test signal and an information signal are converted to a recording data signal, a light source is driven based on the recording data signal, and the test signal and the information signal are recorded on an optical information recording medium or in an erasing mode in which light is irradiated onto the optical information recording medium with a predetermined erase power by driving the light source and thus information is erased from the optical information recording medium; a reproducing means that reproduces signals from the optical information recording medium; and a recording condition determination means that allows the recording/erasing means to operate in the erasing mode to erase information in an area for carrying out test recording on the optical information recording medium, then allows the recording/erasing means to operate in the recording mode to record the test signal supplied from the test signal generation means in the area, and determines a proper value for edge positions of recording pulses in the recording data signal based on a result obtained by reproducing the test signal from the area by the reproducing means.
According to this configuration, the area intended for the test recording on the optical information recording medium assumes an initialized condition regardless of the states of recording marks that previously have been recorded. Therefore, shifts in interval between edges in the test signal are not caused, thus optimizing the edge positions in the recording data signal further precisely.
In order to attain the aforementioned object, a first optical information recording method comprises steps of: (a) generating a test signal; (b) shifting, at random in each sector, a start point of the test recording of the test signal generated on an optical information recording medium; (c) converting the test signal shifted at random to a recording data signal, driving a light source based on the recording data signal, and carrying out the test recording in a plurality of sectors on the optical information recording medium; (d) reproducing the test signal recorded at the step (c) from each of the plurality of sectors on the optical information recording medium; (e) calculating an average of results obtained by reproducing the test signal; and (f) determining edge positions of recording pulses in the recording data signal based on the average calculated.
According to this method, the recording start point of the test signal recorded in each of the plurality of sectors on the optical information recording medium is shifted at random in each sector. Therefore, recording marks that previously have been recorded in the area intended for the test recording and recording marks of the test signal overwritten thereon overlap in random conditions in each sector. Thus, shifts in interval between edges in the test signal that are caused by mark distortion produced by the overwriting of the recording marks of the test signal on the recording marks that previously have been recorded are averaged. Consequently, variation caused by the phase relation between the recording marks that previously have been recorded on the optical information recording medium and the recording marks of the test signal does not occur in values of the intervals between edges that are calculated from test signals reproduced. As a result, the interval between edges of recording marks of the test signal can be calculated precisely, thus providing an optical information recording apparatus that can record information signals precisely by optimizing edge positions in the recording data signal.
In order to attain the aforementioned object, a second optical information recording method of the present information comprises steps of: (a) generating a data pattern having substantially no correlation with a test signal used for the above-mentioned test recording; (b) converting the data pattern generated to a recording data signal, driving a light source based on the recording data signal, and recording the data pattern in an area for carrying out the test recording on an optical information recording medium; (c) generating the test signal; (d) converting the test signal generated to a recording data signal, driving the light source based on the recording data signal, and overwriting the test signal in the area on the optical information recording medium; (e) reproducing the test signal overwritten at the step (d) from the area on the optical information recording medium; and (f) determining a proper value for edge positions of recording pulses in the recording data signal based on a result obtained by reproducing the test signal.
According to this method, before the test recording carried out on the optical information recording medium, the data pattern having substantially no correlation with the test signal is recorded in the area intended for the test recording and therefore recording marks of the test signal overwritten in the area and recording marks that previously have been recorded overlap in random conditions. Thus, shifts in interval between edges in the test signal that are caused by mark distortion produced by the overwriting of the recording marks of the test signal on the recording marks that previously have been recorded are averaged. Consequently, variation caused by the phase relation between the recording marks that previously have been recorded on the optical information recording medium and the recording marks of the test signal does not occur in values of the intervals between edges that are calculated from test signals reproduced. As a result, the interval between edges of recording marks of the test signal can be calculated precisely, thus providing an optical information recording apparatus that can record information signals precisely by optimizing edge positions in the recording data signal.
It is preferable that the second optical information recording method further comprises a step of shifting a recording start point at random in each sector on the optical information recording medium and in this step the recording start point at least of the test signal is shifted at random.
According to this method, shifts in interval between edges in the test signal that are caused by the overwriting of the recording marks of the test signal on the recording marks that previously have been recorded can be further averaged, thus optimizing the edge positions in the recording data signal further precisely.
In the second optical information recording method, it is preferable that the data pattern is a random pattern.
According to this method, since a random pattern is recorded in the area intended for the test recording, shifts in interval between edges in the test signal that are caused by the overwriting of the recording marks of the test signal on the recording marks that previously have been recorded can be further averaged, thus enabling an optimum value for edge positions in the recording data signal to be determined further precisely.
In order to attain the aforementioned object, a third optical information recording method of the present information comprises steps of: (a) erasing information in an area for carrying out the above-mentioned test recording from an optical information recording medium by driving a light source to irradiate light onto the optical information recording medium with a predetermined erase power; (b) generating a test signal; (c) converting the test signal generated to a recording data signal, driving the light source based on the recording data signal, and recording the test signal in the area for carrying out the test recording on the optical information recording medium; (d) reproducing the test signal recorded at the step (c) from the area on the optical information recording medium; and (e) determining a proper value for edge positions of recording pulses in the recording data signal based on a result obtained by reproducing the test signal.
According to this method, the area intended for the test recording on the optical information recording medium assumes an initialized condition regardless of the states of recording marks that previously have been recorded. Therefore, shifts in interval between edges in the test signal are not caused, thus optimizing the edge positions in the recording data signal further precisely.
In order to attain the aforementioned object, a fourth optical information recording apparatus of the present invention comprises: a test signal generation means that generates an edge test signal and a power test signal; a recording means that converts the edge test signal, the power test signal, and an information signal to a recording data signal, drives a light source based on the recording data signal, and records the edge test signal, the power test signal, and the information signal on an optical information recording medium; a recording pulse edge adjusting means that adjusts edge positions of recording pulses in the recording data signal; a reproducing means that reproduces signals from the optical information recording medium; a first recording condition determination means that allows the test signal generation means to supply the edge test signal to the recording means to record the edge test signal on the optical information recording medium and determines a set value for the edge positions of recording pulses for the recording pulse edge adjusting means based on a result obtained by reproducing the edge test signal from the optical information recording medium by the reproducing means; and a second recording condition determination means that allows the test signal generation means to supply the power test signal to the recording means to record the power test signal on the optical information recording medium and determines a set value of recording power of the light source for the recording means based on a result obtained by reproducing the power test signal from the optical information recording medium by the reproducing means. In the fourth optical information recording apparatus, the first recording condition determination means determines a proper value for the edge positions of recording pulses for the recording pulse edge adjusting means based on a result obtained by reproducing an edge test signal recorded with a recording power whose set value is an initial value. The second recording condition determination means determines a proper value of the recording power of the light source for the recording means based on a result obtained by reproducing the power test signal recorded with edge positions of recording pulses of which the set value determined by the first recording condition determination means is the proper value.
According to this configuration, after the determination of the proper value for the edge positions of recording pulses, test recording is further carried out with the recording pulses that have been set to the proper value to optimize the recording power, thus optimizing both the edge positions of recording pulses and the recording power. Therefore, information signals can be recorded precisely on the optical information recording medium.
It is preferable that the fourth optical information recording apparatus further comprises a recording start point shifting means that shifts a recording start point at random in each sector on the optical information recording medium when the test recording of the edge test signal is carried out.
According to this configuration, shifts in interval between edges in the test signals that are caused by the overwriting of the recording marks of the test signals on recording marks that previously have been recorded in the area intended for the test recording on the optical information recording medium can be averaged, thus optimizing the edge positions in the recording data signal further precisely.
It is preferable that the fourth optical information recording apparatus further comprises a data pattern generation means that generates a data pattern having substantially no correlation with the edge test signal and the data pattern is recorded before the test recording of the edge test signal by the recording means in an area where the edge test signal is to be recorded on the optical information recording medium.
According to this configuration, the correlation between the recording marks of the test signals overwritten in the area intended for the test recording and recording marks that previously have been recorded is further decreased. Therefore, shifts in interval between edges in the test signals can be averaged, thus optimizing the edge positions in the recording data signal further precisely.
In the fourth optical information recording apparatus, it is preferable that the first recording condition determination means is provided with a means for comparing an interval between edges in the edge test signal and that in a reproduction signal obtained by reproducing the edge test signal from the optical information recording medium to determine the proper value for the edge positions of recording pulses.
It is preferable that the fourth optical information recording apparatus further comprises a measurement means for measuring either a bit error rate or jitter of the reproduction signal obtained by reproducing the edge test signal from the optical information recording medium and the first recording condition determination means determines an edge position of a recording pulse that allows a measurement result by the measurement means to be the minimum as the proper value.
It is preferable that the fourth optical information recording apparatus further comprises a measurement means for measuring either a bit error rate or jitter of a reproduction signal obtained by reproducing the power test signal from the optical information recording medium and the second recording condition determination means determines the proper value of the recording power based on a recording power value that allows a measurement result by the measurement means to be a predetermined value or less.
In the fourth optical information recording apparatus, it is preferable that the second recording condition determination means determines the initial value of the recording power of the light source for the recording means based on a result obtained by reproducing the power test signal recorded with edge positions of recording pulses of which the set value determined by the first recording condition determination means is a predetermined value.
According to this configuration, both the edge positions of recording pulses and the recording power can be optimized further precisely, thus enabling information signals to be recorded on the optical information recording medium precisely.
Further, it is preferable that a measurement means for measuring either a bit error rate or jitter of a reproduction signal obtained by reproducing the power test signal from the optical information recording medium is further provided and the second recording condition determination means determines the proper value of the recording power based on a recording power value that allows a measurement result by the measurement means to be a predetermined value or less and uses the proper value as the initial value of the recording power.
In order to attain the aforementioned object, a fourth optical information recording method comprises steps of: (a) setting recording power of a light source to an initial value and recording an edge test signal on an optical information recording medium; (b) determining a proper value for edge positions of recording pulses based on a result obtained by reproducing the edge test signal recorded at the step (a) from the optical information recording medium; (c) setting the edge positions of recording pulses to the proper value determined at the step (b) and recording a power test signal on the optical information recording medium; and (d) determining a proper value of the recording power based on a result obtained by reproducing the power test signal recorded at the step (c) from the optical information recording medium.
In this method, after the determination of the proper value for the edge positions of recording pulses, test recording is further carried out with the recording pulses that have been set to the proper value, thus optimizing the recording power. Consequently, both the edge positions of recording pulses and the recording power can be optimized, thus enabling information signals to be recorded on the optical information recording medium precisely.
In the fourth optical information recording method, it is preferable that a recording start point on the optical information recording medium is shifted at random in each sector at the step (a).
According to this method, shifts in interval between edges in the test signal that are caused by the overwriting of the recording marks of the test signal on recording marks that previously have been recorded in the area intended for the test recording on the optical information recording medium can be averaged, thus optimizing the edge positions in the recording data signal further precisely.
It is preferable that the fourth optical information recording method comprises, before the step (a), a step of recording a data pattern having substantially no correlation with the edge test signal and the power test signal in the area for carrying out the test recording on the optical information recording medium.
According to this method, the correlation between the recording marks of the test signal overwritten in the area intended for the test recording and recording marks that previously have been recorded is further decreased. Therefore, shifts in interval between edges in the test signal can be averaged, thus optimizing the edge positions in the recording data signal further precisely.
In the fourth optical information recording method, it is preferable that the step (b) comprises a step of comparing an interval between edges in the edge test signal and that in a reproduction signal obtained by reproducing the edge test signal from the optical information recording medium.
Alternatively, in the fourth optical information recording method, it is preferable that the step (b) comprises a step of measuring either a bit error rate or jitter of the reproduction signal obtained by reproducing the edge test signal from the optical information recording medium to determine an edge position of a recording pulse that allows a measurement result to be the minimum as the proper value.
In the fourth optical information recording method, it is preferable that the step (d) comprises a step of measuring either a bit error rate or jitter of a reproduction signal obtained by reproducing the power test signal from the optical information recording medium to determine the proper value of the recording power based on a recording power value that allows a measurement result to be a predetermined value or less.
It is preferable that the fourth optical information recording method further comprises, prior to the step (a), steps of: (e-1) recording the power test signal on the optical information recording medium with edge positions of recording pulses being set to a predetermined value; and (e-2) determining a proper value of the recording power based on a result obtained by reproducing the power test signal recorded at the step (e-1) from the optical information recording medium, and the proper value of the recording power determined at the step (e-2) is used as the initial value of the recording power at the step (a).
Thus, both the edge positions of recording pulses and the recording power can be optimized further precisely, thus enabling information signals to be recorded on the optical information recording medium precisely.
Further, it is preferable that the step (e-2) comprises a step of measuring either a bit error rate or jitter of the reproduction signal obtained by reproducing the power test signal from the optical information recording medium to determine the proper value of the recording power based on a recording power value that allows a measurement result to be a predetermined value or less.
In order to attain the aforementioned object, a fifth optical information recording apparatus of the present invention comprises: a test signal generation means that generates an edge test signal and a power test signal; a recording means that converts the edge test signal, the power test signal, and an information signal to a recording data signal, drives a light source based on the recording data signal, and records the edge test signal, the power test signal, and the information signal on the optical information recording medium; a recording pulse edge adjusting means that adjusts edge positions of recording pulses in the recording data signal; a reproducing means that reproduces signals from the optical information recording medium; a first recording condition determination means that allows the test signal generation means to supply the edge test signal to the recording means to record the edge test signal on the optical information recording medium and determines a set value for the edge positions of recording pulses for the recording pulse edge adjusting means based on a result obtained by reproducing the edge test signal from the optical information recording medium by the reproducing means; and a second recording condition determination means that allows the test signal generation means to supply the power test signal to the recording means to record the power test signal on the optical information recording medium and determines a set value of recording power of the light source for the recording means based on a result obtained by reproducing the power test signal from the optical information recording medium by the reproducing means. In the fifth optical information recording apparatus, the second recording condition determination means determines a proper value of the recording power of the light source for the recording means based on a result obtained by reproducing the power test signal recorded with the edge positions of recording pulses whose set value is an initial value. The first recording condition determination means determines a proper value for the edge positions of recording pulses for the recording pulse edge adjusting means based on a result obtained by reproducing the edge test signal recorded with a recording power of which the set value determined by the second recording condition determination means is the above-mentioned proper value.
According to this configuration, after the determination of the proper value of the recording power, test recording is further carried out with the recording power set to the proper value, thus optimizing the edge positions of recording pulses. Consequently, both the edge positions of recording pulses and the recording power can be optimized, thus enabling information signals to be recorded on the optical information recording medium precisely.
It is preferable that the fifth optical information recording apparatus further comprises a recording start point shifting means that shifts a recording start point at random in each sector on the optical information recording medium when the test recording of the edge test signal is carried out.
According to this configuration, shifts in interval between edges in the test signals that are caused by the overwriting of the recording marks of the test signals on recording marks that previously have been recorded in the area intended for the test recording on the optical information recording medium can be averaged, thus optimizing the edge positions in the recording data signal further precisely.
It is preferable that the fifth optical information recording apparatus further comprises a data pattern generation means that generates a data pattern having substantially no correlation with the edge test signal and the data pattern is recorded before the test recording of the edge test signal by the recording means in the area where the edge test signal and the power test signal are to be recorded on the optical information recording medium.
According to this configuration, the correlation between the recording marks of the test signals to be overwritten in the area intended for the test recording and recording marks that previously have been recorded is further decreased. Therefore, shifts in interval between edges in the test signals can be averaged, thus optimizing the edge positions in the recording data signal further precisely.
It is preferable that the fifth optical information recording apparatus further comprises a measurement means for measuring either a bit error rate or jitter of a reproduction signal obtained by reproducing the power test signal from the optical information recording medium and the second recording condition determination means determines the proper value of the recording power based on a recording power value that allows a measurement result by the measurement means to be a predetermined value or less.
In the fifth optical information recording apparatus, it is preferable that the first recording condition determination means is provided with a means for comparing an interval between edges in the edge test signal and that in a reproduction signal obtained by reproducing the edge test signal from the optical information recording medium to determine the proper value for the edge positions of recording pulses.
It is preferable that the fifth optical information recording apparatus further comprises a measurement means for measuring either a bit error rate or jitter of the reproduction signal obtained by reproducing the edge test signal from the optical information recording medium and the first recording condition determination means determines an edge position of a recording pulse that allows a measurement result by the measurement means to be the minimum as the proper value.
In the fifth optical information recording apparatus, it is preferable that the first recording condition determination means determines the initial value for the edge positions of recording pulses for the recording pulse edge adjusting means based on the result obtained by reproducing the edge test signal recorded with recording power of which the set value determined by the second recording condition determination means is a predetermined value.
Thus, both the edge positions of recording pulses and the recording power can be optimized further precisely, thus enabling information signals to be recorded on the optical information recording medium precisely.
Further, it is preferred to further comprises a recording start point shifting means that shifts a recording start point at random in each sector on the optical information recording medium when the test recording of the edge test signal is carried out.
In addition, it is preferable that a data pattern generation means that generates a data pattern having substantially no correlation with the edge test signal is further provided and the data pattern is recorded before the test recording of the edge test signal by the recording means in the area where the edge test signal is to be recorded on the optical information recording medium.
It is preferable that the first recording condition determination means is provided with a means for comparing an interval between edges in the edge test signal and that in the reproduction signal obtained by reproducing the edge test signal from the optical information recording medium to determine a proper value for the edge positions of recording pulses.
It is preferable that a measurement means for measuring either a bit error rate or jitter of the reproduction signal obtained by reproducing the edge test signal from the optical information recording medium is further provided, the first recording condition determination means determines an edge position of a recording pulse that allows a measurement result by the measurement means to be the minimum as a proper value, and the proper value for the edge positions of recording pulses thus determined is used as the initial value.
In order to attain the aforementioned object, a fifth optical information recording method of the present invention comprises steps of: (a) setting edge positions of recording pulses to an initial value and recording a power test signal on an optical information recording medium; (b) determining a proper value of recording power of a light source based on a result obtained by reproducing the power test signal recorded at the step (a) from the optical information recording medium; (c) recording an edge test signal on the optical information recording medium based on the recording power determined at the step (b); and (d) determining a proper value for the edge positions of recording pulses based on a result obtained by reproducing the edge test signal recorded at the step (c) from the optical information recording medium.
In this method, after the determination of the proper value of the recording power, test recording is further carried out with the recording power set to the proper value, thus optimizing the edge positions of recording pulses. Consequently, both the edge positions of recording pulses and the recording power can be optimized, thus enabling information signals to be recorded on the optical information recording medium precisely.
In the fifth optical information recording method, it is preferable that a recording start point on the optical information recording medium is shifted at random in each sector at the step (c).
According to this method, shifts in interval between edges in the test signals that are caused by the overwriting of the recording marks of the test signals on recording marks that previously have been recorded in the area intended for the test recording on the optical information recording medium can be averaged, thus optimizing the edge positions in the recording data signal further precisely.
It is preferable that the fifth optical information recording method comprises, before the step (c), a step of recording a data pattern having substantially no correlation with the edge test signal in the area for carrying out the test recording on the optical information recording medium.
According to this method, the correlation between the recording marks of the test signals to be overwritten in the area intended for the test recording and recording marks that previously have been recorded is further decreased. Therefore, shifts in interval between edges in the test signals can be averaged, thus optimizing the edge positions in the recording data signal further precisely.
In the fifth optical information recording method, it is preferable that the step (b) comprises a step of measuring either a bit error rate or jitter of a reproduction signal obtained by reproducing the power test signal from the optical information recording medium and the proper value of the recording power is determined based on a recording power value that allows the measurement result to be a predetermined value or less.
In the fifth optical information recording method, it is preferable that the step (d) comprises a step of comparing an interval between edges in the edge test signal and that in a reproduction signal obtained by reproducing the edge test signal from the optical information recording medium.
In the fifth optical information recording method, it is preferable that the step (d) comprises a step of measuring either a bit error rate or jitter of the reproduction signal obtained by reproducing the edge test signal from the optical information recording medium and an edge position of a recording pulse that allows a measurement result to be the minimum is determined as the proper value.
It is preferable that the fifth optical information recording method further comprises, prior to the step (a), steps of: (e-1) recording the edge test signal on the optical information recording medium with recording power being set to a predetermined value; and (e-2) determining a proper value for the edge positions of recording pulses based on a result obtained by reproducing the edge test signal recorded at the step (e-1) from the optical information recording medium, and the proper value for the edge positions of recording pulses determined at the step (e-2) is used as the initial value for the edge positions of recording pulses at the step (a).
Thus, both the edge positions of recording pulses and the recording power can be optimized further precisely, thus enabling information signals to be recorded on the optical information recording medium precisely.
Further, it is preferable that a recording start point on the optical information recording medium is shifted at random in each sector at the step (e-1).
It is preferred to comprise, before the step (e-1), a step of recording a data pattern having substantially no correlation with the edge test signal in the area for carrying out the test recording on the optical information recording medium.
It is preferable that the step (e-2) comprises a step of comparing an interval between edges in the edge test signal and that in the reproduction signal obtained by reproducing the edge test signal from the optical information recording medium.
It is preferable that the step (e-2) comprises a step of measuring either a bit error rate or jitter of the reproduction signal obtained by reproducing the edge test signal from the optical information recording medium and an edge position of a recording pulse that allows a measurement result to be the minimum is determined as the proper value.
In order to attain the aforementioned object, a sixth optical information recording apparatus of the present invention comprises: a test signal generation means that generates a test signal; a recording means that converts the test signal and an information signal to a recording data signal, drives a light source based on the recording data signal, and records the test signal and the information signal on an optical information recording medium; a polarity inverting means that inverts polarity of the recording data signal; a polarity inversion control means that supplies only one of an inverted signal and a non-inverted signal of the recording data signal converted from the test signal to the recording means when test recording is carried out and any one selected at random in each sector from an inverted signal and a non-inverted signal of the recording data signal converted from the information signal to the recording means when the information signal is recorded; a recording pulse edge adjusting means that adjusts edge positions of recording pulses in the recording data signal; a reproducing means that reproduces signals from the optical information recording medium; and a recording condition determination means that determines a proper value for the edge positions of recording pulses based on a result obtained by reproducing the test signal from the optical information recording medium by the reproducing means and supplies the proper value to the recording pulse edge adjusting means.
According to this configuration, the number of times the optical information recording medium can be rewritten increases and an optical information recording apparatus that can record information signals precisely under the recording conditions optimized by the test recording can be provided.
It is preferable that the sixth optical information recording apparatus further comprises a recording start point shifting means that shifts a recording start point of the recording data signal at random in each sector on the optical information recording medium.
According to this configuration, shifts in interval between edges in the test signal that are caused by the overwriting of the recording marks of the test signal on recording marks that previously have been recorded in the area intended for the test recording on the optical information recording medium can be averaged, thus optimizing the edge positions in the recording data signal further precisely.
It is preferable that the sixth optical information recording apparatus further comprises a data pattern generation means that generates a data pattern having substantially no correlation with the test signal and the data pattern is recorded on a track intended for the test recording before the test recording is carried out.
According to this configuration, the recording marks of the test signal overwritten in the area intended for the test recording and recording marks that previously have been recorded overlap in random conditions. Therefore, shifts in interval between edges in the test signal can be averaged, thus optimizing the edge positions in the recording data signal further precisely.
In the sixth optical information recording apparatus, it is preferable that the recording condition determination means is provided with a means for comparing an interval between edges in the test signal and that in a reproduction signal obtained by reproducing the test signal from the optical information recording medium to determine the proper value for the edge positions of recording pulses.
It is preferable that the sixth optical information recording apparatus further comprises a measurement means for measuring either a bit error rate or jitter of the reproduction signal obtained by reproducing the test signal from the optical information recording medium, and the recording condition determination means determines an edge position of a recording pulse that allows a measurement result by the measurement means to be a predetermined value or less as the proper value.
It is preferable that the sixth optical information recording apparatus is provided with a second test signal generation means that generates a second test signal and a second recording condition determination means. The second recording condition determination means records any one of an inverted signal and a non-inverted signal of the second test signal on the optical information recording medium with edge positions of recording pulses being set to the proper value by the recording pulse edge adjusting means, and the inverted signal and the non-inverted signal are supplied from the second test signal generation means and have been selected at random in each sector by the polarity inversion control means. Then the second recording condition determination means determines a proper value of the recording power of the light source for the recording means based on a result obtained by reproducing the second test signal from the optical information recording medium by the reproducing means.
In test recording for determining the recording power, there is a high possibility that the test recording is carried out with a higher recording power than that used in test recording for determining the edge positions of recording pulses and in normal recording of information signals. According to this configuration, in the test recording for determining the recording power, the test recording is carried out while inverting the polarity of the second test signal at random, thus preventing a recording film in the area intended for the test recording on the optical information recording medium from being deteriorated.
Further, it is preferable that the sixth optical information recording apparatus further comprises a measurement means for measuring either a bit error rate or jitter of a reproduction signal obtained by reproducing the second test signal from the optical information recording medium, and the second recording condition determination means determines the proper value of the recording power based on a recording power value that allows a measurement result by the measurement means to be a predetermined value or less.
In order to attain the aforementioned object, a sixth optical information recording method comprises steps of: (a) determining randomly whether the polarity of a first test signal is to be inverted and carrying out test recording of only one of an inverted signal and a non-inverted signal of the first test signal on a predetermined track of an optical information recording medium; (b) determining a proper value for edge positions of recording pulses based on a result obtained by reproducing the first test signal that has been recorded at the step (a) from the optical information recording medium; and (c) selecting, at random in each sector, any one of an inverted signal and a non-inverted signal of an information signal to be recorded on the optical information recording medium and recording a selected signal on the optical information recording medium with edge positions of recording pulses being set to the proper value determined at the step (b).
According to this method, the number of times the optical information recording medium can be rewritten increases and information signals can be recorded precisely under the recording conditions optimized by the test recording.
In the sixth optical information recording method, it is preferable that a recording start point on the optical information recording medium is shifted at random in each sector at the step (a).
According to this method, shifts in interval between edges in the test signal that are caused by the overwriting of the recording marks of the test signal on recording marks that previously have been recorded in the area intended for the test recording on the optical information recording medium can be averaged, thus optimizing the edge positions in the recording data signal further precisely.
It is preferable that the sixth optical information recording method comprises, before the step (a), a step of recording a data pattern having substantially no correlation with the first test signal on the predetermined track.
According to this method, the recording marks of the test signal overwritten in the area intended for the test recording and recording marks that previously have been recorded overlap in random conditions. Therefore, shifts in interval between edges in the test signal can be averaged, thus optimizing the edge positions in the recording data signal further precisely.
In the sixth optical information recording method, it is preferable that the step (b) comprises a step of comparing an interval between edges in the first test signal and that in a reproduction signal obtained by reproducing the first test signal from the optical information recording medium.
In the sixth optical information recording method, it is preferable that the step (b) comprises a step of measuring either a bit error rate or jitter of the reproduction signal obtained by reproducing the first test signal from the optical information recording medium and an edge position of a recording pulse that allows a measurement result to be the minimum is determined as the proper value.
It is preferable that the sixth optical information recording method further comprises, between the steps (b) and (c), a step (b-1) of selecting any one of an inverted signal and a non-inverted signal of a second test signal at random in each sector and recording a selected signal on the optical information recording medium with edge positions of recording pulses being set to the proper value determined at the step (b), and a step (b-2) of determining a proper value of the recording power based on a result obtained by reproducing the second test signal recorded at the step (b-1) from the optical information recording medium.
In test recording for determining the recording power, there is a high possibility that the test recording is carried out with a higher recording power than that used in test recording for determining the edge positions of recording pulses and in normal recording of information signals. According to this method, at the step (b-1) of carrying out the test recording for determining the recording power, the test recording is carried out while inverting the polarity of the second test signal at random, thus preventing a recording film in the area intended for the test recording on an optical information recording medium from being deteriorated.
Further, it is preferable that the step (b-2) comprises a step of measuring either a bit error rate or jitter of a reproduction signal obtained by reproducing the second test signal from the optical information recording medium and a proper value of the recording power is determined based on a recording power value that allows a measurement result to be a predetermined value or less.
In order to attain the aforementioned object, a seventh optical information recording method of the present invention employs an optical information recording medium with a Z-CLV format in which a plurality of zones including a predetermined number of tracks are comprised in a recording area, the number of sectors around the disk recording medium increases gradually from an inner zone toward an outer zone, and recording linear density decreases gradually from an inner circumference toward an outer circumference within one zone. In the seventh optical information recording method, test recording is carried out on the optical information recording medium before an information signal is recorded on the optical information recording medium. The seventh optical information recording method is characterized by comprising a step (a) of carrying out the test recording for recording a test signal with substantially the same recording linear density as that of an information signal on an innermost track in each zone and a step (b) of determining a proper value for either edge positions of recording pulses or recording power based on a result obtained by reproducing the test signal from the optical information recording medium.
According to this method, an excellent result as to jitter (or an excellent bit error rate) can be obtained throughout from an innermost circumference to an outermost circumference in each zone and therefore information signals can be recorded precisely.
In the seventh optical information recording method, it is preferable that the step (b) comprises a step of measuring either a bit error rate or jitter of a reproduction signal obtained by reproducing the test signal from the optical information recording medium and the proper value of the recording power is determined based on a recording power value that allows a measurement result to be a predetermined value or less.
In the seventh optical information recording method, it is preferable that at the step (a), the track for the test recording is located substantially at an innermost circumference at least in one zone.
In the seventh optical information recording method, it is preferable that at the step (a), the track for the test recording is located at the inner or outer side with respect to the recording area on the optical information recording medium.
In order to attain the aforementioned object, a first optical information recording medium of the present invention is an optical information recording medium with a Z-CLV format in which a plurality of zones including a predetermined number of tracks are comprised in a recording area, the number of sectors around the recording medium increases gradually from an inner zone toward an outer zone, and recording linear density decreases gradually from an inner circumference toward an outer circumference within one zone. The first optical information recording medium is characterized by having an area for test recording substantially at an innermost circumference at least in one of the zones.
In order to attain the aforementioned object, a second optical information recording medium of the present invention is an optical information recording medium with a Z-CLV format in which a plurality of zones including a predetermined number of tracks are comprised in a recording area, the number of sectors around the recording medium increases gradually from an inner zone toward an outer zone, and recording linear density decreases gradually from an inner circumference toward an outer circumference within one zone. The second optical information recording medium is characterized by having a test recording area at inner and outer sides with respect to the recording area and the recording linear density in the test recording area is substantially the same as that of an information signal on an innermost track in each zone within the recording area.
In the first and second optical information recording media, it is preferable that a recording film is formed of a phase-change material.
In the first to sixth optical information recording apparatuses, it is preferable that test recording and recording conditions are set at least at one time selected from the times: in adjusting the optical information recording apparatus; on starting the optical information recording apparatus; after a lapse of a predetermined time from the starting; in exchanging the optical information recording medium; when a bit error rate of the optical information recording medium exceeds a predetermined value; and when environmental temperature changes.
According to this configuration, variable factors among optical information recording apparatuses can be compensated by carrying out test recording in adjusting the recording/reproducing apparatuses. Variable factors in an optical information recording apparatus itself can be compensated by carrying out test recording on starting the optical information recording apparatus and after a lapse of a predetermined time from the starting. In addition, by carrying out test recording in exchanging an optical information recording medium, variable factors between optical information recording media can be compensated. Further, by carrying out test recording when a bit error rate of an optical information recording medium exceeds a predetermined value, variable factors in the optical information recording medium itself can be compensated. By carrying out test recording when environmental temperature changes, variable factors caused by the temperature dependency of an optical information recording apparatus and an optical information recording medium can be compensated.
The optical information recording apparatus that records information on an optical information recording medium by the first to seventh optical information recording methods is characterized by setting test recording and recording conditions at least at one time selected from the times: in adjusting the recording/reproducing apparatus; on starting the recording/reproducing apparatus; after a lapse of a predetermined time from the starting; in exchanging the optical information recording medium; when a bit error rate of the optical information recording medium exceeds a predetermined value; and when environmental temperature changes.
According to this configuration, variable factors among optical information recording apparatuses can be compensated by carrying out test recording in adjusting the recording/reproducing apparatuses. Variable factors in an optical information recording apparatus itself can be compensated by carrying out test recording on starting the optical information recording apparatus and after a lapse of a predetermined time from the starting. In addition, by carrying out test recording in exchanging an optical information recording medium, variable factors between optical information recording media can be compensated. Further, by carrying out test recording when a bit error rate of an optical information recording medium exceeds a predetermined value, variable factors in the optical information recording medium itself can be compensated. By carrying out test recording when environmental temperature changes, variable factors caused by the temperature dependency of an optical information recording apparatus and an optical information recording medium can be compensated.
Moreover, in the first to sixth optical information recording apparatuses, it is preferable that a recording film of the optical information recording medium is formed of a phase-change material.
In the first to seventh optical information recording methods, it is preferable that a recording film of the optical information recording medium is formed of a phase-change material.